There are many prior art documents disclosing different methods for achieving prefabricated accommodation. RU2240400 describes a shipping container-like structure which concertinas into a flat package for transportation. When erected It constitutes an extremely rudimentary box shaped structure.
WO 96/13402 shows a more sophisticated folding structure pivoted to a central unit provided with wheels for transportation. When on location supporting bearers extend from the central unit and additional modules unfold from either side of the central unit to sit on the bearers. The side modules have gabled roofs and end walls fold out from the sides of the central unit to form closed structures. This construction is costly and only suitable for transportation by towing behind a prime mover.
U.S. Pat. No. 4,780,996 teaches a folding portable building construction with a rigid central section and a winching system for the erection of roof members of complementary side modules. Wall members and flooring unfold after the roof members are winched into place. The winching system can be removed after erection which makes the system independent of erecting cranes but adds to the cost.
SU1803507 and U.S. Pat. No. 4,912,891 teach further variations on the theme of a rigid central unit with unfolding side modules. However this rigid central unit construction is bulky and difficult to transport. Accordingly there is a need for a prefabricated building which can be transported as a flat package like that of RU2240400 but which provides more habitable accommodation when erected on location.